1. Field of Use
The invention relates to machines for making non-cylindrical paper containers. In particular, it relates to machines for making such containers by wrapping a pre-formed blank around a non-cylindrical mandrel with a pair of wings, each of which has pivotably attached thereto a supplement wing portion to enable wrapping the blank around the mandrel without obstruction of the wing or wing portion by the non-cylindrical mandrel.
2. Description of the Prior Art
Paper containers can be produced in a variety of ways. One widely known method of paper container manufacture is described in my U.S. Pat. No. 2,942,530, issued June 28, 1960, and also in my U.S. Pat. No. 3,745,891, issued July 17, 1973, both patents being entitled "Blank Wrapping Mechanism for Frusto-Conical Cup-Making Machines". These patents describe a method in which a pre-formed paper blank is automatically loaded at a point below a cylindrical or frusto-conical mandrel. A pair of wrapping arms or wings then engage the body blank, causing it to be wrapped around the mandrel with one end of the blank slightly overlapping the other so that the ends may be attached to each other by heat-sealing or with glue to form a seam. Each wing of the pair shown in the machines described in the two prior art patents is a one-piece wing. The wings substantially conform to the shape of the mandrels, and move smoothly and without obstruction from the blank-loading position away from the mandrel to the blank-wrapping position adjacent and around the mandrel.
A one-piece wing, however, is not suitable for wrapping blanks on mandrels of a substantially non-cylindrical cross-section, such as elongated or rectangular cross-sections. If a one-piece wing were used on a cup-making machine as shown in the prior art, but with substantially rectangular mandrels and wings shaped to conform thereto, that portion of each wing intended to contact and squeeze the blank against the uppermost portion of the mandrel would, at its end, strike the side of the mandrel, making it impossible to wrap the blank. This problem renders a blank forming machine useless for anything but substantially cylindrical containers.